Block copolymers containing poly(dimethyl siloxane) (PDMS) are well known. Typically, these are linear copolymers made up of long sequences of PDMS covalently coupled to another polymer. For example, diblock, triblock, and segmented/multiblock copolymers of PDMS with a variety of polymers have been prepared.
Block copolymers of PDMS with other polymers typically phase separate as a result of the immiscibility of the two different blocks. However, due to the covalent linkage between the blocks, the phase separation is restricted and only micro- or nano-scale phase separation occurs. In many PDMS block copolymer systems, PDMS has a significantly lower surface energy than the second block, and thus tends to predominate on the surface of the copolymer.
Block copolymers of PDMS with polyurethane are also known. In many cases, these may function as minimally adhesive surfaces. However, over time, the more hydrophilic polyurethane components may migrate to the surface resulting in a loss of the low surface energy. This is especially a problem when the copolymer is exposed to an aqueous environment (e.g., when used as a marine coating, etc.).
Accordingly, it would be desirable to provide an improved polymeric material, particularly one that is capable of forming stable surface microdomains when exposed to water. It would also be desirable to provide an improved polymeric material having a defined topography.